Treatment and prevention of streptococcal pharyngitis in adults and children

INTRODUCTION — Group A Streptococcus (GAS), or Streptococcus pyogenes, is the leading bacterial cause of tonsillopharyngitis in adults and children worldwide. GAS is one of the few causes of tonsillopharyngitis or pharyngitis for which antibiotic treatment is recommended.

The treatment and prevention of group A streptococcal tonsillopharyngitis is reviewed here. The clinical features and diagnostic evaluation of patients with tonsillopharyngitis are discussed separately. (See "Group A streptococcal tonsillopharyngitis in children and adolescents: Clinical features and diagnosis" and "Evaluation of acute pharyngitis in adults".)

DEFINITIONS — Group A Streptococcus (GAS) can cause symptomatic infection or can colonize the oropharynx.

●Active infection refers to symptomatic infection caused by GAS.

●Persistent infection refers to symptomatic infection caused by GAS that does not resolve after appropriate antibiotic treatment. This is synonymous with treatment failure.

●Recurrent infection refers to a new symptomatic infection with GAS that occurs after appropriate antibiotic treatment. Recurrent infection can be caused by the same GAS serotype that caused the initial infection or by a different serotype. Recurrent infections most often occur among members of the same household or in other settings such as schools or daycare centers where close contact facilitates GAS transmission [1].

●Chronic carriage refers to asymptomatic colonization or the persistent presence of GAS in the oropharynx in the absence of symptoms or host immune response. The prevalence of chronic carriage has not been comprehensively studied, but reported rates are about 4 to 5 percent in healthy adults [2] and range from about 2 to 20 percent in children [2-9]. Carriage can persist for months to years [8,10].

Distinguishing among these states is important. In general, only patients with symptomatic GAS infection require treatment. Exceptions include patients with a history of acute rheumatic fever, and chronic GAS carriers during outbreaks of acute rheumatic fever and/or poststreptococcal glomerulonephritis, or when GAS infections are recurring in households or other close-contact settings.

GOALS OF TREATMENT — The goal of antibiotic therapy for streptococcal pharyngitis is multifold and includes:

●Reducing symptom severity and duration

●Prevention of acute complications, such as otitis media, peritonsillar abscesses, or other invasive infections

●Prevention of delayed complications or immune sequelae, particularly acute rheumatic fever

●Prevention of spread to others

Symptom reduction — Antibiotic treatment has been shown to reduce symptom severity and hasten the rate of recovery in patients with streptococcal pharyngitis [11,12]. However, even without antibiotic therapy, symptoms typically resolve in about three to five days for most patients [13], making the prevention of complications a key goal of care.

Prevention of complications — Complications of streptococcal pharyngitis can result from extension of infection beyond the oropharynx, termed suppurative complications, or as immune phenomena, termed nonsuppurative complications. Suppurative complications of GAS pharyngitis include otitis media, peritonsillar cellulitis or abscess, sinusitis, meningitis, bacteremia, and necrotizing fasciitis. Nonsuppurative complications of GAS pharyngitis include acute rheumatic fever, poststreptococcal glomerulonephritis, and reactive arthritis. The spectrum of complications associated with streptococcal pharyngitis is discussed in detail separately. (See "Complications of streptococcal tonsillopharyngitis".)

Suppurative complications — Rates of otitis media and peritonsillar abscesses are each reduced with antibiotic use. In a large meta-analysis of randomized trials comparing antibiotics to placebo in adults and children with streptococcal pharyngitis, antibiotics reduced the incidence of acute otitis media within 14 days (0.47 versus 2.0 percent; risk ratio [RR] 0.30, 95% CI 0.15-0.58) and peritonsillar abscess at two months (0.24 versus 2.3 percent; RR 0.15, 95% CI 0.05-0.47) [11]. Reduction in the rates of acute sinusitis were also observed but did not reach statistical significance. The effect on less common but severe suppurative complications including bacteremia and necrotizing fasciitis has not been studied, though it is reasonable to surmise that antibiotics would have a protective effect.

Nonsuppurative complications

Acute rheumatic fever — The prevention of acute rheumatic fever is one of the main indications for antibiotic treatment of streptococcal pharyngitis. Acute rheumatic fever and rheumatic heart disease are important causes of cardiovascular death worldwide [14,15]. In a meta-analysis of 14 randomized trials comparing penicillin with placebo in over 8000 adults and children with sore throat, penicillin decreased the risk of rheumatic fever by about two-thirds [11]. The absolute risk reduction is likely highest in children aged 5 to 15 residing in developing nations, where incidence of rheumatic fever peaks [15,16]. Additional detail on acute rheumatic fever is provided separately. (See "Acute rheumatic fever: Epidemiology and pathogenesis" and "Acute rheumatic fever: Clinical manifestations and diagnosis" and "Acute rheumatic fever: Treatment and prevention".)

Other nonsuppurative complications — Data on the benefits of antibiotics in preventing other nonsuppurative complications are limited. Antibiotics probably prevent poststreptococcal glomerulonephritis based on a meta-analysis of 10 randomized trials comparing antibiotics with placebo in adults and children with sore throat, though there were too few cases in these trials to conclude this with certainty [11]. The effect of antibiotics on other nonsuppurative complications such as poststreptococcal arthritis and pediatric autoimmune neuropsychiatric disorder associated with group A streptococci (PANDAS) is not well studied. Additional details on these complications are provided separately. (See "Poststreptococcal glomerulonephritis" and "Complications of streptococcal tonsillopharyngitis".)

Prevention of transmission — GAS can spread among close contacts, leading to clusters of cases and recurrent infections in households or other close-contact settings. The rate of GAS transmission from an infectious case to close contacts is estimated to be between 5 and 50 percent [17-19]. Although no studies have directly evaluated the effect of antibiotic treatment on transmission, antibiotic use appears to eliminate GAS from the oropharynx in about 80 to 90 percent of cases after 24 hours of therapy [20,21]. When untreated, historic epidemiologic data suggest approximately 50 percent of patients with streptococcal pharyngitis will continue to harbor GAS in the oropharynx three to four weeks after symptom onset [13,22].

WHOM TO TREAT — We recommend antibiotic treatment for any patient with symptomatic pharyngitis or tonsillopharyngitis who has a positive microbiologic test (ie, nucleic acid amplification test [NAAT], rapid antigen test, or culture) for group A Streptococcus (GAS) (algorithm 1). (See "Evaluation of acute pharyngitis in adults", section on 'Evaluation' and "Group A streptococcal tonsillopharyngitis in children and adolescents: Clinical features and diagnosis".)

Empiric treatment is generally not recommended, as the clinical features of GAS pharyngitis and nonstreptococcal pharyngitis broadly overlap (figure 1) [23,24]. Short delays in therapy (eg, while awaiting culture results) have not been associated with increased rates of complications such as acute rheumatic fever [22]. However, whether such delays effect rates of other complications (eg, development of peritonsillar abscess) is not known. If clinical suspicion for GAS pharyngitis is high and testing results cannot be obtained rapidly, it is reasonable to start antibiotic treatment while test results are pending [25]. If testing does not confirm the diagnosis, antibiotics should be discontinued.

Antibiotic treatment is not recommended for asymptomatic chronic GAS carriers or for GAS carriers who have superimposed viral infections [23,24,26]. (See 'Chronic GAS carriers' below.)

TREATMENT OF INITIAL EPISODES — Antibiotic treatment is the mainstay of care. (Related Pathway(s): Streptococcal pharyngitis in adults: Treatment.)

Supportive care measures such as nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen may be administered to relieve fever and pain.

Antibiotic treatment — The antibiotic treatment recommendations presented below are largely consistent with recommendations from the Infectious Diseases Society of America, the American Heart Association, and the American Academy of Pediatrics (algorithm 2) [23,26-28]. Guidelines from other regions vary [29-31].

Penicillin — Penicillin is the treatment of choice for group A Streptococcus (GAS) pharyngitis due to its efficacy, safety, narrow spectrum, and low cost. Resistance to penicillin among clinical GAS isolates has not been documented. Penicillin is the only antibiotic that has been studied and shown to reduce rates of acute rheumatic fever [11]. Dosing and duration of therapy are outlined in the tables (table 1 and table 2).

●For most adult patients, we use oral penicillin V 500 mg two to three times daily for 10 days. Oral amoxicillin is also a reasonable option.

●For most children, we use either oral penicillin V or amoxicillin. Amoxicillin is often preferred for young children because the taste of the amoxicillin suspension is more palatable than that of penicillin. Amoxicillin can also be given once daily. In several randomized trials, standard-dose and once-daily dosing of amoxicillin appeared to have equivalent efficacy as oral penicillin [32-36].

●For patients with a history of acute rheumatic fever who are not receiving antibiotic prophylaxis, we select among oral penicillin V, oral amoxicillin, or a single dose of intramuscular (IM) penicillin G benzathine. Because adherence is critical for patients with a history of acute rheumatic fever, we base our choice on patient values and preferences. While IM benzathine penicillin can be given as a single dose, the drug is expensive in some regions, frequently unavailable, and causes injection site pain. In contrast, oral options are readily available but carry the risk of incomplete adherence. (See "Acute rheumatic fever: Treatment and prevention".)

The duration of therapy for oral penicillin or amoxicillin is 10 days. Although symptoms typically improve within the first few days of treatment [13,37,38], treating for 10 days appears to enhance the rate of GAS eradication from the oropharynx when compared with 5 or 7 days [3,23,39-41]. One randomized trial directly compared a 5-day course of penicillin V 800 mg four times daily with a 10-day course of penicillin V dosed at 1000 mg three times daily in 433 patients (age ≥6) with microbiologically confirmed streptococcal pharyngitis [42]. Clinical cure rates were similar between groups (89.6 versus 93.8 percent; difference -4.2, 95% CI -9.9 to 1.5); however, wide confidence intervals suggest that treatment differences may become apparent with a larger sample size. In addition, bacterial eradication rates were lower in the 5-day treatment group (80.4 versus 90.7 percent). Complication rates were also similar between groups but their overall frequency was low (1 percent). Because complications, particularly immune sequelae, are likely related to the presence of GAS in oropharynx and can be severe, treating with a 10-day course seems prudent.

IM penicillin appears to be more effective than oral penicillin at eradication of GAS from the oropharynx [43] and has been most well studied for the prevention of acute rheumatic fever [11]. However, as noted above, IM penicillin is expensive in some regions and not always available. Thus, for patients with a history of acute rheumatic fever (who are high risk for cardiac complications compared with those without this history), we discuss the risk and benefits of its use on an individual basis.

Alternatives to penicillin — Cephalosporins, clindamycin, and macrolides are alternatives for patients who are allergic to penicillin or who cannot otherwise tolerate penicillin. Dosing and duration of therapy are outlined in the tables (table 1 and table 2).

Selection of an agent depends on the type of allergy, local antibiotic resistance rates, and patient values and preferences (table 3 and algorithm 2).

The approach to antibiotic selection for patients with penicillin allergy varies among experts:

●For patients with mild, non-IgE-mediated reactions to penicillin (eg, maculopapular rash beginning days into therapy), the author and editors of this topic generally select a first-generation cephalosporin such as cephalexin because of its narrow spectrum and the low likelihood of cross-reactivity.

For patients with mild, possibly IgE-mediated reactions (eg, urticaria or angioedema but not anaphylaxis), they use a second- or third-generation cephalosporin with a side chain that is dissimilar to penicillin, such as cefuroxime, cefdinir, or cefpodoxime.

When using an oral cephalosporin, we generally treat for 10 days. A five-day treatment course with cefdinir or cefpodoxime is also acceptable. These shorter treatment courses are US Food and Drug Administration approved and, in randomized trials, had similar clinical and microbiologic efficacy as 10-day courses of oral penicillin [44-47].

●For patients with a history of severe angioedema and/or anaphylaxis or with serious delayed reactions or for patients who cannot take cephalosporins, we generally use a macrolide, such as azithromycin. A major advantage of azithromycin is that it can be given for a three- or five-day course due to its extended half-life [48].

A key consideration when using a macrolide is potential drug resistance. Macrolide resistance rates are growing and vary with geography [49-54]. Generally, higher macrolide resistance rates have been observed in Asia and Europe when compared with the United States. Clinicians should take into account local resistance patterns or consult local antibiograms when prescribing macrolides, if possible.

●For patients with known or suspected macrolide-resistant GAS who cannot tolerate cephalosporins, we treat with a 10-day course of clindamycin.

The above approach is generally consistent with recommendations from both the American Academy of Pediatrics and the Infectious Diseases Society of America [23,28].

Other experts, including UpToDate allergy specialists, prefer to perform a test-dose procedure before prescribing cephalosporins to patients with penicillin allergies (algorithm 3). Because this is generally not feasible in the outpatient clinic, a more conservative approach to treatment is an option for patients with mild, non-IgE-mediated reactions or IgE-mediated reactions:

●For patients with mild, non-IgE-mediated reactions, a third-generation cephalosporin, such as cefpodoxime or cefdinir, is selected.

●For patients with any possible IgE-mediated reactions (including anaphylaxis), an alternative to cephalosporins such as a macrolide or clindamycin is selected.

The approach to the management of patients with penicillin allergy is reviewed separately. (See "Choice of antibiotics in penicillin-allergic hospitalized patients".)

No clinically relevant differences in symptom resolution were detected in a meta-analysis of 19 randomized trials comparing cephalosporins, macrolides, or clindamycin with either penicillin or amoxicillin in over 5000 adults or children with GAS [55]. While the incidence of clinical relapse was lower when comparing treatment with cephalosporins versus penicillins (26 versus 46 per 1000 patients; odds ratio 0.55, 95% CI 0.30-0.99), broad use of cephalosporins may promote antimicrobial resistance and are generally more costly than penicillins. No trial has evaluated the use of alternatives to penicillin for the prevention of acute rheumatic fever; thus, penicillin remains the treatment of choice when feasible.

Tetracyclines, sulfonamides, and fluoroquinolones should not be used for treatment of streptococcal pharyngitis due to the high prevalence of resistance [49-54], potential for clinical failure, and/or high side-effect profile [56].

Adjunctive treatment — We offer supportive care (rest, adequate fluid intake, avoidance of respiratory irritants, soft diet) to all patients and systemic agents such as NSAIDs or acetaminophen for patients who desire medication for fever or pain control. We avoid using systemic glucocorticoids for symptom relief because antibiotics and systemic analgesics are generally effective, and the addition of systemic glucocorticoids increases the likelihood of adverse events.

Symptomatic treatment for sore throat is discussed in detail separately. (See "Acute pharyngitis in children and adolescents: Symptomatic treatment" and "Symptomatic treatment of acute pharyngitis in adults".)

RESPONSE TO THERAPY

Resolution of symptoms — Fever and constitutional symptoms typically resolve within one to three days of starting treatment [13,57-61]. Follow-up visits are not needed for most patients.

Most patients can return to work or school after completing one full day of treatment, provided they are afebrile and otherwise well. This recommendation is based on a small cohort study in children that showed that about 80 percent of patients with culture-proven group A streptococcal (GAS) pharyngitis clear the organism from the oropharynx within 24 hours of starting therapy [20]. A second cohort study evaluating 111 children with pharyngitis and a positive rapid antigen detection test (RADT) showed that 91 percent of patients treated with amoxicillin by 5:00 PM on the day of therapy had negative follow-up RADTs the following morning [21].

Indications for test of cure — For patients who are asymptomatic at the end of a course of antibiotic therapy, a test of cure is typically not needed [62]. We generally perform a test of cure (culture or RADT) in the following patients, who are at risk for complications, recurrent infection, or spreading infection to others:

●Patients with a history of acute rheumatic fever

●Patients who acquired infection during an outbreak of acute rheumatic fever or poststreptococcal glomerulonephritis

●Patients who acquired infection during a cluster of cases in their household or other close-contact setting

For patients who test positive in these circumstances, we repeat a full 10-day course of therapy. We usually select an antibiotic that has greater beta-lactamase stability than the one used for the initial treatment course. As examples, if penicillin was used for initial treatment, we use either amoxicillin-clavulanate or a first-generation cephalosporin; if a first-generation cephalosporin was used, we select a later-generation cephalosporin. The rationale for this strategy is based on clinical data that suggest relapse rates may be lower with cephalosporin use, as well as scientific observations that antibiotics with greater beta-lactamase activity may be more effective in eradicating GAS from the oropharynx. (See 'Antibiotic treatment' above.)

We do not treat patients who are asymptomatic following an appropriate course of therapy who test positive but lacked an appropriate indication for a test of cure. The patients are likely chronic carriers. (See 'Definitions' above.)

Persistent or recurrent symptoms

Evaluation — For patients who have persistent or recurrent symptoms consistent with GAS pharyngitis after completing a course of antibiotic therapy, we generally repeat testing for GAS. Because chronic GAS carriage can occur after antibiotic therapy [2-9], we generally avoid testing in patients whose symptoms are highly consistent with viral pharyngitis (eg, sore throat accompanied by cough, conjunctivitis, or rhinorrhea) or other etiology. For patients with persistent or recurrent symptoms consistent with GAS pharyngitis, a positive test result should raise suspicion for any of the following:

●Nonadherence with the prescribed antimicrobial regimen

●Recurrent infection, which refers to new infection with the initial infecting strain or a new strain

●Persistent infection, also termed treatment failure

●Infection with a different pathogen superimposed on chronic GAS carriage

●Presence of a suppurative complication, such as a peritonsillar abscess

Distinguishing among these states is typically based on epidemiologic and clinical history, which can be challenging as symptoms overlap and GAS testing can be positive in all.

Suspicion for recurrent infection should be raised when clusters of GAS infections are occurring within the patient's household, school, workplace, or other close-contact setting. Symptoms associated with recurrent infection with the same serotype may be milder than with the initial infection [63]. Persistent infection is rare but most often occurs in children, particularly those under age 5 [64]. Initial antibiotic choice may also influence the likelihood of recurrent or persistent infection. Selection of an antibiotic to which there is potential GAS resistance, such as a macrolide or clindamycin, increases the likelihood of treatment failure. Additionally, some studies suggest that cephalosporins may be more effective than penicillin for preventing relapse [65].

The presence of persistent or recurrent symptoms should also raise suspicion for an alternate initial diagnosis or new infection with a different pathogen in a chronic GAS carrier. For patients with repeated episodes of pharyngitis, culturing for GAS when patients are between episodes may help distinguish chronic carriage from active infection. A positive culture in an asymptomatic patients suggests that the patient is a carrier and that symptoms are due to an alternate cause (table 4 and table 5). Additional details on the evaluation of acute pharyngitis are discussed separately. (See "Evaluation of acute pharyngitis in adults" and "Group A streptococcal tonsillopharyngitis in children and adolescents: Clinical features and diagnosis".)

A persistent, severe sore throat accompanied by fever, trismus, or a muffled voice suggests a local complication such as peritonsillar cellulitis or abscess. These diagnoses are discussed separately. (See "Complications of streptococcal tonsillopharyngitis" and "Peritonsillar cellulitis and abscess".)

Antibiotic treatment — We generally repeat a 10-day course of antibiotic treatment for patients with persistent or recurrent streptococcal pharyngitis. The selection of an antibiotic varies based on patient history (table 1).

●For patients who were nonadherent to the initial antibiotic regimen, we typically treat with intramuscular penicillin. Injections of penicillin G benzathine provide bactericidal levels against GAS for 21 to 28 days. For those who are allergic or who cannot otherwise tolerate penicillin, we individualize antibiotic selection based on the patient's preferences and reasons for nonadherence.

●For patients with persistent infection or an initial recurrence, we usually select an antibiotic that has greater beta-lactamase stability than the one used for the initial treatment course. As examples, if penicillin was used for initial treatment, we use either amoxicillin-clavulanate or a first-generation cephalosporin; if a first-generation cephalosporin was used, we select a later-generation cephalosporin (table 6).

The approach is based on a meta-analyses of four randomized trials evaluating over 1300 adults and children with GAS pharyngitis that showed decreased clinical relapse rates when comparing cephalosporins with penicillins (25 versus 46 percent; odds ratio 0.55, 95% CI 0.30-0.99) [66]. Additional studies suggest that bacteriologic cure rates may be higher for cephalosporins compared with penicillin [67-70]. Scientific observations also support the selection of antibiotics with beta-lactamase stability when treating persistent or recurrent GAS infection [71-73]. Some bacteria that colonize the oropharynx, such as Staphylococcus aureus, Haemophilus influenza, and Moraxella catarrhalis, produce beta-lactamases that inactivate penicillin, leading to decreased activity of penicillin against GAS [74-76]. Penicillin also decreases the quantity of alpha-streptococci in the oropharynx, which naturally protect against GAS infection [77-79]. Cumulatively, these effects may inadvertently promote the survival and persistence of GAS in the oropharynx. By contrast, antibiotics with beta-lactamase activity may have a more balanced effect on the oropharyngeal flora, resulting in greater likelihood of GAS eradication.

A small number of patients experience multiple recurrences, which may be related to the infecting GAS strain [80-82], host immune response [58,83], or other factors that are not yet well characterized.

●For patients with multiple recurrences of GAS pharyngitis, we attempt treatment with an antibiotic from a class that has not been used previously, such as clindamycin.

●For patients with frequent, mild to moderate recurrent infections, delaying the start of antibiotic therapy by two to three days is an alternate approach. This approach is derived from observational data that suggest delaying therapy may allow the development of immunity against the infecting strain, resulting in higher eradication rates [58,64,83] without increasing the risk of acute rheumatic fever [84,85]. We generally avoid this approach in patients with severe symptoms or when GAS is actively circulating in the community, as it prolongs symptom duration and may increase the risk of suppurative complications and/or transmission of GAS to others.

●For patients with frequent, severe episodes of GAS pharyngitis that recur despite appropriate antibiotic treatment, we consider tonsillectomy. (See 'Tonsillectomy' below.)

It is not necessary to perform follow-up testing for persistent or recurrent infection unless the patient becomes symptomatic after antibiotic treatment or special circumstances as outlined above are present. (See 'Indications for test of cure' above.)

When recurrent infections are thought to be due to ongoing GAS circulation among household members, we consider testing all household members and treating those who test positive. When recurrent infections are thought to be due to ongoing GAS circulation in other close-contact settings such as daycare centers or workplaces, we determine the best management approach on a case-by-case basis.

Tonsillectomy — Tonsillectomy is rarely indicated for patients with recurrent GAS pharyngitis. We determine the need for tonsillectomy in each individual case based on the patient age, the frequency and severity of infections, history of antibiotic use, and patient values and preferences.

Detailed indications for tonsillectomy in adults and children with recurrent pharyngitis and supporting evidence are discussed separately. (See "Tonsillectomy and/or adenoidectomy in children: Indications and contraindications", section on 'Recurrent throat infection' and "Tonsillectomy in adults: Indications", section on 'Recurrent and chronic pharyngotonsillitis'.)

PREVENTION

General prevention

Hand hygiene — Hand hygiene is a key measure for preventing spread to others, especially after coughing or sneezing and before preparing foods or eating, and we remind all patients of its importance.

Postexposure prophylaxis — Testing and treatment of asymptomatic persons who have been exposed to a patient with group A Streptococcus (GAS) pharyngitis are not routinely recommended [23], except for patients with a history of acute rheumatic fever, during outbreaks of acute rheumatic fever and/or poststreptococcal glomerulonephritis, or when GAS infections are recurring in households or other close-contact settings.

Special populations

Patients with a history of acute rheumatic fever — Patients with a history of acute rheumatic fever are at high risk for recurrent rheumatic fever and the development of chronic valvular heart disease with any subsequent GAS infection. We educate these patients on the risk of recurrence and its complications and recommend long-term antibiotic prophylaxis. Antibiotic selection and duration of therapy vary based on patient characteristics and medication availability (table 7 and table 8).

Details on acute rheumatic fever, rheumatic heart disease, and their prevention are discussed separately. (See "Acute rheumatic fever: Clinical manifestations and diagnosis" and "Acute rheumatic fever: Treatment and prevention" and "Clinical manifestations and diagnosis of rheumatic heart disease" and "Management and prevention of rheumatic heart disease".)

Chronic GAS carriers — Antibiotic treatment is not routinely recommended for chronic carriers [23]. Carriers are unlikely to transmit group A Streptococcus (GAS) to others [62,86,87] and are at very low risk for developing suppurative complications or acute rheumatic fever [10]. However, we do consider treating carriers during outbreaks of acute rheumatic fever and/or poststreptococcal glomerulonephritis or when GAS infections are recurring in households or other close-contact settings.

Oral options for treatment of chronic carriage include clindamycin, amoxicillin-clavulanate, and penicillin plus rifampin; the duration of treatment is usually 10 days [23]. When used with either oral or parenteral penicillin, rifampin is typically given only during the last four days of therapy.

Prevention of foodborne illness — Streptococcal contamination of food has been implicated in foodborne outbreaks of pharyngitis [88-92], and foodborne transmission of GAS pharyngitis by asymptomatic food service workers with nasopharyngeal carriage has been reported [91,93,94]. Factors that can reduce foodborne transmission of GAS pharyngitis include thorough cooking, complete reheating, and use of gloves while handling food [88,95].

Vaccination — No vaccine against GAS is available for clinical use. However, research on GAS vaccine development is ongoing [96-100]. An important area of uncertainty is whether vaccine-induced antibodies may cross-react with host tissue to produce nonsuppurative sequelae in the absence of clinical infection.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Streptococcal tonsillopharyngitis".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Strep throat in adults (The Basics)" and "Patient education: Strep throat in children (The Basics)" and "Patient education: Scarlet fever (The Basics)")

●Beyond the Basics topics (see "Patient education: Sore throat in children (Beyond the Basics)" and "Patient education: Sore throat in adults (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS

●Importance of treatment – Group A Streptococcus (GAS), or Streptococcus pyogenes, is the leading bacterial cause of tonsillopharyngitis in adults and children worldwide. GAS is one of the few causes of tonsillopharyngitis or pharyngitis for which antibiotic treatment is recommended. (See 'Introduction' above.)

The goals of antibiotic therapy for GAS pharyngitis include symptom relief, preventing complications, and preventing transmission to others. (See 'Goals of treatment' above.)

●Treatment recommendations

•Whom to treat – We recommend antibiotic treatment for any patient with symptomatic pharyngitis or tonsillopharyngitis who has a positive microbiologic test (ie, nucleic acid amplification test [NAAT], rapid antigen test, or culture) for GAS (Grade 1A). We generally do not treat patients who do not have microbiologic confirmation of infection or who are chronic carriers. (See 'Whom to treat' above.)

•Preferred treatment for adults – For most adults, we treat with oral penicillin V 500 mg two to three times daily for a total of 10 days. Penicillin is the treatment of choice for GAS pharyngitis due to its efficacy, safety, narrow spectrum, and low cost (table 1 and algorithm 2). (See 'Antibiotic treatment' above.)

•Preferred treatment for children – For most children, we use either oral penicillin V or amoxicillin. For young children, amoxicillin is often preferred because the taste of the amoxicillin suspension is more palatable than that of penicillin (table 2 and algorithm 2). (See 'Antibiotic treatment' above.)

•Treatment for patients with a history of acute rheumatic fever – For patients with a history of acute rheumatic fever who are not receiving antibiotic prophylaxis, we select among oral penicillin V, oral amoxicillin, or a single dose of intramuscular penicillin G benzathine. The choice is based on drug availability, cost, likelihood of adherence with oral therapy, and patient values and preferences (table 1 and table 2 and algorithm 2). (See 'Antibiotic treatment' above.)

•Alternatives for patients who cannot tolerate penicillin – For patients who are allergic to or who cannot tolerate penicillin, alternatives include cephalosporins, clindamycin, and macrolides. Selection among these agents is based on the nature of the drug allergy or intolerance and local antibiotic resistance rates (table 3 and table 1 and table 2 and algorithm 2). (See 'Alternatives to penicillin' above.)

●Symptom resolution and return to work – Fever and sore throat typically resolve within one to three days. Most patients can return to work, school, or daycare after 12 to 24 hours of antibiotic therapy, provided they are afebrile and otherwise well. (See 'Resolution of symptoms' above.)

A test of cure is usually not needed for patients who are asymptomatic at the end of a course of antibiotic therapy, except for those with a history of acute rheumatic fever or in other special circumstances. (See 'Indications for test of cure' above.)

●Management of persistent symptoms after a course of antibiotics – For patients who have persistent or recurrent symptoms after completing a course of antibiotic therapy, we repeat microbiologic testing when symptoms are compatible with GAS infection. Because chronic GAS carriage can occur after antibiotic therapy, we generally avoid testing in patients who have symptoms that are more compatible with viral pharyngitis or other etiology. (See 'Persistent or recurrent symptoms' above.)

For patients with microbiologically proven recurrent or persistent GAS pharyngitis, we repeat a 10-day course of antibiotic therapy (Grade 2C) and generally select an antibiotic that has greater beta-lactamase stability than the one used initially. Tonsillectomy is rarely indicated for such patients. (See 'Antibiotic treatment' above and 'Tonsillectomy' above.)

●Prophylaxis for patients with a history of acute rheumatic fever – Antibiotic prophylaxis is used for patients with a history of acute rheumatic fever because these patients are at high risk for recurrence and for the development of chronic valvular heart disease. Antibiotic prophylaxis is not recommended for chronic carriers, except in special circumstances. (See 'Prevention' above.)